The present application is related to a fixture for facilitating the calibration and alignment of vehicle safety system sensors, and in particular, to a movable fixture supporting vehicle wheel alignment system imaging sensors and at least one calibration or alignment target associated with a vehicle safety system sensor.
Vehicle wheel measurement systems, such as wheel alignment or inspection systems employing machine vision technology, such as cameras observing optical targets mounted on various surfaces within associated fields of view are well known in the vehicle measurement, alignment, and inspection industry. Typically, these type of systems employ two or four cameras, mounted to a crossbeam member on a fixture or structure located in front of a vehicle service area. The cameras are oriented such that each wheel of a vehicle to be inspected (or target mounted thereon) within the service area is visible to at least one of the cameras. The structure supporting the camera crossbeam may be fixed in place, or may be configured to be moved from one service area to another as needed. The camera crossbeam itself may be vertically (and/or rotationally) adjustable to accommodate vehicles at different elevations of a lift rack within the vehicle service. Images acquired by the cameras are conveyed to a wheel alignment processing system configured with suitable software instructions for image evaluation, determining various spatial measurements associated with the observed surfaces, and ultimately for identifying vehicle wheel alignment angles from associated spatial measurements.
When it is necessary to realign or recalibrate various vehicle safety system sensors, such as radar units or optical sensors typically utilized in forward collision avoidance systems or adaptive cruise control systems, specialized structures are precisely positioned in front of the vehicle, often with the aid of a vehicle measurement system such as a wheel alignment or inspection system. For example, U.S. Pat. No. 7,382,913 B2 to Dorrance describes a method and apparatus for guiding placement of a vehicle service apparatus relative to a vehicle, based on measurements acquired by a separate vehicle wheel alignment measurement system. Other techniques for guiding placement of a specialized structure relative to a vehicle undergoing a realignment or recalibration of a vehicle safety system sensor include the use of laser emitters and leveling devices, such as shown in U.S. Pat. No. 6,583,868 B2 to Hopfenmuller.
The particular type and configuration of onboard sensors utilized in the safety systems of vehicles vary between different vehicle manufacturers, and often, between different models of vehicles from the same manufacturer. Different types of onboard sensors have different realignment or recalibration procedures, and often requiring the specialized structures to be placed at different locations relative to the vehicle. In some cases, the placement of the specialized structures conflicts with the placement or positioning of the fixture or structure supporting the cameras associated with the vehicle measurement system.
Accordingly, there is a need to provide a positionable fixture or support structure capable of supporting both the set of cameras associated with a vehicle measurement system as well as the specialized structures required for realignment or recalibration of onboard vehicle safety system sensors, thereby reducing the total number of fixtures required to complete a vehicle onboard sensor realignment or recalibration, and eliminating potential spatial conflicts between support structures and specialized structures.
Some specialized structures or optical targets used in the alignment or calibration of onboard vehicle safety system sensors cannot be secured to the positionable fixture or support structure. Accordingly, there is a need to provide a system to guide an operator in the proper placement of those specialized support structures or optical targets relative to either the vehicle undergoing service or to the positionable fixture or support structure itself.